Fiber opening device for separating individual fibers from a fiber sliver

ABSTRACT

A fiber opening device for use in a discontinuous spinning process. The opening device includes an opening roller rotatably mounted about an axis and having a cylindrical working surface which extends around the axis. Opening elements are provided around the working surface. A space is defined between an axially outermost fiber opening element and an adjacent outer edge of the cylindrical working surface. A pressure reduction opening is provided for reducing pressure in or around that space. The pressure reduction opening is arranged to urge fibers into engagement with the working surface.

TECHNICAL FIELD AND BACKGROUND OF THE INVENTION

This invention relates to a fibre opening device for use in adiscontinuous spinning process and particularly, although notexclusively, to a fibre opening device for an open end spinning machine.

In an open end spinning machine, the flow of fibrous material from feedsliver to yarn is interrupted in that the fibres are fed to a fibreopening device in the form of a rotatably mounted opening roller havinga cylindrical working surface around which fibre opening elements areprovided. The fibre opening elements may be integrated with the workingsurface or attached thereto, for example, in the form of carding wire.The fibre opening device separates the fibres of the sliver, theseparated fibres then being transferred to a spinning rotor.

The Applicant has noted that, towards the outer edges of the cylindricalworking surface of a fibre opening device, the fibre sliver tends toride up away from the fibre opening elements and, in some cases, thesliver rides up over parts of the opening device which are disposedadjacent to the outer edges of the working surface. Thus, in use, fibreswhich are disposed towards the outer edges of the working surface arenot separated fully and this may lead to defects in the yarn quality.

It is an object of the present invention to alleviate this problem.

Another factor which affects the quality of fibre produced in open endspinning is the presence of microdust in the spinning rotor. Microdust,which is believed to comprise small particles which are torn from thefibres themselves, may gradually build up between adjacent fibre openingelements on the working surface of the opening device. In this case, thepresence of microdust may reduce the effectiveness of the openingelements in separating fibres. Furthermore, microdust may gradually bedeposited in the groove of a spinning rotor which may consequentlyreduce the effectiveness of the spinning rotor and the quality of theyarn formed therein.

Many attempts have been made to reduce the level of microdust. Forexample, European Patent Application No. 0 348 178 (Stewart) discloses afibre opening device for use with a discontinuous spinning process, thedevice comprising a rotatably mounted hollow opening roller having acylindrical working surface from which fibre opening elements project.Holes, which are interspersed with the fibre opening elements, extendthrough the working surface of the roller and communicate with a hollowregion within the roller. A vacuum suction device and a compressed airjet device, provided in the hollow region, are operated when necessaryto remove dust, trash and short fibres which pass through the holes inthe working surface and which would otherwise remain adhered to aninterior cylindrical surface of the opening roller.

SUMMARY OF THE INVENTION

The vacuum suction device and compressed air jet device described is anintermittently operable device for the removal of dust, trash and shortfibres which adds significantly to the complexity and cost of the fibreopening device. It is an object of a preferred embodiment of the presentinvention, to provide a less complex means of reducing the level ofmicrodust.

According to one aspect of the present invention, there is provided afibre opening device for use in a discontinuous spinning process, theopening device comprising a rotatably mounted opening roller having acylindrical working surface around which fibre opening elements areprovided, a space being defined between an axially outermost fibreopening element and an outer edge of the cylindrical working surface,wherein a pressure reduction means is provided for reducing pressure inor around that space such that fibres may be urged into engagement withthe working surface of the opening roller.

With such a device, the free head-ends of the fibres may be urged intoengagement with the working surface of the opening roller, just beforethe tail-ends of the fibres are released from a clamping point between afeed roller and a feed table arrangement, since once the fibres havebeen released it may not be possible to guide and direct fibres in acontrolled manner.

The provision of such a fibre opening device may reduce the number offibres which are not engaged with the fibre opening elements of theworking surface and, accordingly, may increase the parallelization andseparation of fibres by the opening device and reduce defects in theyarn quality.

The fibres are preferably urged in a substantially radial direction intoengagement with the working surface of the opening roller.

Preferably, said pressure reduction means includes a passageway, a firstend of which opens in or adjacent to said space. A second end of thepassageway may open in an area which, with the fibre opening device inuse, is at a lower pressure than the pressure in or around the space sothat pressure in or above the space may be reduced by the flow of airalong said passageway from said first end to said second end.

Preferably, said passageway remains open for all rotational positions of;he opening roller. Thus, suitably, air flows along said passageway inuse for all rotational positions of the opening roller. Preferably, thecross-sectional area of the passageway is fixed and unadjustable in theassembled fibre opening device.

In a preferred embodiment, an opening (for example, a hole or slot) maybe provided through the cylindrical working surface in said space forproviding said pressure reduction means. Said opening preferably leadsinto said passageway via said first end thereof.

A second end of the passageway preferably opens through a side of theopening roller. A chamber is preferably provided in said passageway.Said chamber is preferably symmetrically disposed about the rotationalaxis of the opening roller. Said chamber is preferably annular, thechamber being co-axial with the rotational axis of the opening roller.Said chamber preferably opens through a side wall of the opening rollerthereby defining the second end of said passageway. Preferably, anannular opening which leads into the annular chamber is defined in saidside wall of the opening roller, said annular opening being co-axialwith a hub or a bearing housing of the opening roller. Preferably, aninner cylindrical wall of said annular opening in said side wall isdefined by a part of the hub or bearing housing. The radial width ofsaid annular opening may be greater than 0.1 mm. Preferably, the radialwidth of said annular opening is greater than 0.5 mm. More preferably,the radial width is greater than 2 mm. The radial width may be greaterthan 3 mm. The provision of a chamber as described may, firstly,increase the efficiency of pressure reduction by said pressure reductionmeans and, secondly, increase the quantity of microdust which may beremoved from fibres being separated by the opening device.

In another embodiment, an opening (for example, a hole or slot) may beprovided adjacent to the opening roller, suitably in a part which facesan end of the opening roller, said opening suitably leading into a saidpassageway in order to provide said pressure reduction means.Preferably, said opening is radially inward of the periphery of saidopening element and is axially spaced therefrom. Said passagewaypreferably extends parallel to the axis of rotation of the openingroller, although it may extend obliquely relative thereto.

Preferably, a plurality of said aforementioned openings and associatedpassageways is provided, said openings being circumferentially spacedaround the working surface of the opening roller at or adjacent to theouter periphery thereof.

Preferably, a pressure reduction means as described in any statementherein is provided adjacent to each outer edge of the cylindricalworking surface. In a preferred embodiment, wherein at least one openingis provided through the cylindrical working surface in a space betweenan outermost fibre opening element and one outer edge of the cylindricalworking surface, and wherein at least one opening is provided throughthe cylindrical working surface in a space between an outermost fibreopening element and the other outer edge of the cylindrical workingsurface, passageways communicating with said openings preferably leadinto a single chamber which may be as described in any statement herein.To achieve this, preferably, a passageway which communicates with eachof said aforementioned openings is provided which extends substantiallyparallel to the axis of rotation of the opening roller.

Preferably, said aforementioned cylindrical working surface of theopening roller is comprised by a ring which is releasably securable to abody of the opening device. The outer cylindrical surface of said ringmay include any of the features of the working surface of the openingroller described in any statement herein. Where the opening deviceincludes a passageway which extends substantially parallel to the axisof rotation of the opening roller, said ring preferably defines, atleast in part, the outer cylindrical boundary of said passageway.

The invention extends to a ring for a fibre opening device as describedin any statement herein, the ring having a cylindrical working surfacewhich includes means for attachment of fibre opening elements or whichincludes fibre opening elements, a space being defined between saidmeans for attachment or said fibre opening elements and an outerperiphery of the ring, wherein an opening is provided in said spacewhich opening extends through said ring.

The opening may be pounded on all sides and, therefore, may be in theform of a hole which extends through the ring. Alternatively, theopening may extend from the outer periphery of the ring and, therefore,may be in the form of a sloe in the ring which extends inwardly fromsaid outer periphery.

The opening may extend in an axial direction through the ring and, inthis case, may be provided in a flange part of the ring which flangepart may extend substantially perpendicularly to the working surface ofthe ring. Preferably, said space is defined between said means forattachment or said fibre opening elements and an outer periphery of thecylindrical working surface, said opening being disposed in said spaceand extending through said working surface, preferably substantiallyradially.

The ring may include any of the features of the working surfacedescribed in any statement herein and may be arranged to be releasablysecured to a fibre opening device as described in any statement herein.

The invention extends to the use of a fibre opening device as describedin any statement herein for urging fibres into engagement with theworking surface of an opening roller of the fibre opening device.

According to a second aspect of the invention, there is provided a fibreopening device for use in a discontinuous spinning process, the openingdevice comprising a rotatably mounted opening roller having acylindrical working surface around which fibre opening elements areprovided, wherein an opening (for example, a hole or slot) is providedthrough said cylindrical working surface, the opening communicating witha passageway which extends within the opening roller and out thereof viaan opening in a side part of the opening roller, the device beingarranged such that, in use, with the opening roller rotating, acontinuous air stream flows through said opening in said cylindricalworking surface, through said passageway and out of said opening in saidside part.

In the invention according to the second aspect, microdust may becarried by said air stream and, therefore, removed continuously in asimple manner. This may obviate the need for intermittent use of avacuum suction device and a compressed air jet device as described abovewith reference to European Patent Application No. 0 348 178.

The fibre opening device of the second aspect may include any of thefeatures of the fibre opening device of the first aspect. For example,in a preferred embodiment of the device according to the second aspect,a chamber as described above is preferably provided in said passageway,the chamber suitably being ring-shaped and co-axial with the rotationalaxis of the opening roller. The chamber preferably opens through thesaid side part of the opening roller.

The invention further extends to the use of a fibre opening device,which comprises a rotatably mounted opening roller having a cylindricalworking surface around which fibre opening elements are provided, anopening being provided through said cylindrical working surface, whichopening communicates with a passageway which extends within the openingroller and out thereof via an opening in a side part of the openingroller, for continuously removing microdust.

Said fibre opening device may be as described in any statement herein.

BRIEF DESCRIPTION OF THE DRAWINGS

Specific embodiments of the invention will now be described, by way ofexample, with reference to the accompanying diagrammatic drawings, inwhich:

FIG. 1 is an end elevation in cross section, of a fibre opening device;

FIG. 2a is a cross-sectional view of part of a fibre opening device;

FIG. 2b is a cross-section along line A--A of FIG. 2a;

FIG. 3a is a cross-sectional view of part of another fibre openingdevice;

FIG. 3b is a side elevation of a ring for a fibre opening device;

FIG. 3c is a cross-section along line B--B of the ring of FIG. 3b;

FIG. 3d is a plan view of the cylindrical surface of the ring, the cardclothing wire or means for attachment thereof being omitted in theinterests of clarity; and

FIG. 4 is a cross-sectional view of part of another fibre openingdevice.

DESCRIPTION OF THE PREFERRED EMBODIMENT AND BEST MODE

The fibre opening device 2, shown in FIG. 1, comprises a housing 4 inwhich a cylindrical fibre opening roller 6, is rotatably mounted. Theroller 6 is provided with a helically wound card clothing wire 8 aroundits cylindrical surface. A feed table 10 and feed roller 13 are arrangedto feed a fibre silver 12 to the opening roller 6. The fibre sliver 12is propelled and separated into individual fibre strands by the rotatingopening roller 6. The surface of the rotating opening roller 6 and fibrestrands 16 carried thereon pass the mouth of a dirt chamber 14, intowhich dirt or other extraneous material from the fibre sliver may fall.Subsequently, the fibre strands 16 are released from engagement with thecard clothing wire 8 and directed into a fibre entry duct 20 in which avacuum prevails. From the fibre entry duct 20, the fibres are directedinto a circumferential groove 22 of a spinning rotor arrangement 24.

Consistent separation of the fibre sliver 12 into individual fibres isonly possible if the fibre sliver 12 contacts the card clothing wire 8,across the whole width thereof. Thus, the transfer of the fibre sliver12 from the feed table and feed roller 13 to the fibre opening roller 6is one critical step in the attainment of consistent separation of thefibre sliver and, in turn, the minimization of yarn defects. Steps inthis transfer process are described below.

The fibre sliver 12 is propelled by the feed roller 13 and at the sametime the card clothing wire 8 of the rotating opening roller 6 tries totake over the fibres. However, as long as the fibres are not releasedfrom being clamped between the feed roller 13 and table 10, onlyparallelisation of fibre strands takes place. It has been noted that,with an opening roller having eleven wire rows, only between six andeight of these wire rows become charged with fibres, this being due, atleast in part, to the helical arrangement of the card clothing wire.

The helix of the card clothing wire 8 leads the fibre strands axially inthe direction of the helix, and as long as the fibre strands are stillheld back by the feed roller 13 and the table 10, the strands move backas soon as they have been guided out to a distance greater than theirstaple length.

During that return movement, the fibres have to run through the linearpitch of the wire teeth and at this moment the fibres are individualisedinto single fibres, having no more contact with each other ("openedend"). At the same moment the fibres are released from being clampedbetween table 10 and feed roll 13, because the feed roll 13 ispropelling the sliver.

It has been noted that, towards each outer edge 30 (FIG. 2a) of thecylindrical fibre opening roller 6, the fibre has a tendency to ride upaway from the card clothing wire 8 and that, furthermore, in some cases,the sliver may ride up over radially outwardly facing surfaces 32 of theopening device 2. Both of these factors lead to inconsistent andincomplete separation of fibres and, consequently, to yarn defects. Theembodiments of FIGS. 2a to 4 are adapted to encourage consistent andmore complete separation of the fibres of the sliver 12. In particular,the embodiments are arranged to urge fibres into engagement with thecard-clothed working surface of the opening roller before the fibres arereleased from being clamped between the feed roller 13 and feed table10.

Referring to FIG. 2a, the fibre opening device 2 includes a generallycylindrical roller body 40 which is fixed to an axle 42. The axle 42includes a threaded bore 44 at one end and, at its other end, is axiallyconnected to an axle 46 which is rotatably mounted in a bearing housing48.

The roller body 40 includes an annular chamber 50 which is axiallyaligned with and disposed around parts of the axles 42 and 46 and thebearing housing 48. The chamber 50 tapers inwardly towards an outersurface 52 of the bearing housing 48 so as to define a narrow annularpassageway 54 which communicates with the chamber 50.

The roller body 40 is arranged to releasably secure an opening rollerring 56 around which the card clothing wire 8 is helically wound. Twoslots 60, 61 are provided in the outer facing cylindrical surface of thering 56. The slots extend inwardly from the outer periphery of the ring.The slots 60, 61 communicate with an axially extending annular part 62of a passageway 64 which leads into the chamber 50. In more detail, theaxially extending annular part 62 of the passageway communicates with afirst radially extending annular part 66 which, in turn, communicateswith a second radially extending bore part 68, the second part 68 beingslightly axially offset relative to the first part 66. The parts 62 and66 are defined by a stepped arrangement of the ring 56 and body 40.

A restraining flange 70 is fixed, by means of a screw 72 engaging thethreaded bore 44, adjacent one end face of the roller body 40 and ring56, to secure the ring 56 in position.

In operation, the roller body 40 is caused to rotate in the direction ofarrow 74 (FIG. 2b). This rotation is believed to cause air to be drawnfrom a region outside the ring 56, through the slot 40 and passageway 64and into the chamber 50. Air may leave the chamber 50 via the passageway54. From the passageway 54, the air enters the dirt chamber 14. An airstream flows continuously as the roller 40 rotates and this is believedto lead to the relief of air pressure in an annular band above the slots60, 61. Accordingly, whilst the fibre sliver is still held back underthe control of the feed table and feed roller (FIG. 1), the fibrestrands disposed above the annular band may be urged, due to thepressure relief and the air flow, into engagement with teeth of the cardclothing wire 8, and, accordingly, the fibres of the sliver may bebrought under control and separated as required by the card clothingwire 8.

It will be noted from FIG. 2b, that the slot 60 is angled in the samedirection as that of the teeth of the card clothing wire 8--that is, atan acute angle to a tangent to the ring 56, measured in the direction ofrotation 74; whereas the slot 61 is angled in an opposite direction tothat of the teeth of the card clothing wire 8--that is, at an obtuseangle to a tangent to the ring 56 measured in the direction of rotation74. It is believed that, with this arrangement, air is drawn intopassageway 64 through slot 60 as discussed above, and a proportion ofthe air drawn in escapes through slot 61.

It has been noted that microdust is carried by the stream of air thatpasses through the slots 60 into the chamber and out of the passageway54 and into the dirt chamber 14. Thus, the apparatus of FIG. 2 mayaffect positively both the separation of fibres of the fibre sliver andalso the removal of microdust therefrom.

The FIG. 2 embodiment only includes slots 60, and associatedpassageways, adjacent to one outer edge of the opening roller 6. In thiscase, since the conveying direction of the helically wound carding wire8 is towards the edge which includes the slots 60, 61, the slots mayrelieve pressure in the region where the accumulation of fibres isgreatest.

Referring now to FIG. 3, the fibre opening device 80 is similar to theFIG. 2 embodiment and like parts in the Figures have the same referencenumerals. The ring 82, however, shown in FIG. 3, includes four radiallyextending slots 84, 86, 88 and 90 which extend through the cylindricalsurface of the ring. Slots 84, 86 are provided in one edge face on theroller 6 adjacent restraining flange 70 and are diametrically oppositeone another; slots 88, 90 are provided in the other edge face of theroller 6 and are diametrically opposite one another.

As shown in FIG. 3b and 3c, the ring 82 includes three axially spacedapart annular webs 92, 94, 96 which project from the inner cylindricalwall 98 of the ring 82 and, in the opening device 80, abut the rollerbody 40. Two diametrically spaced apart axially extending grooves 100are cut into the webs 92, 94, 96 perpendicular thereto, so that, withthe ring in position around the body 40, two diametrically spaced apart,axially extending passageways 102 extend between respective slots 84, 88and slots 86, 90. The passageways 102 communicate with a respectiveradial bore 104 provided in the body 40. Each bore 104 leads intochamber 50.

Thus, when the opening roller 6 rotates, a stream of air may passthrough slots 84, 86, 88, 90 along passageways 102 and radial bores 104into the chamber 50. From the chamber, air passes via passageway 54,into the dirt chamber 14. The passage of the air stream is representedby arrows in FIG. 3a. Microdust may be carried in the air stream asdescribed in relation to the FIG. 2 embodiment.

In order to increase the velocity of the air stream through the openingdevice 80, triangular cross-section part 110 of the body 40 may beremoved so that the chamber 50 opens through the outer face 112 of thebody 40. Thus an annular gap in the face 112 will be defined. The radialdimension of said gap being "x" mm, where x may be 0.5 mm or greater.

Fibre opening devices which are presently available may readily bemodified so that they may benefit from the advantageous effectsdescribed herein. For example, a ring 82, shown in FIG. 3, may be usedin conjunction with the carding roller unit described in U.K. Patent 2114 172 (Stahlecker), so that an air stream may be caused to flowthrough the roller body thereof.

An alternative fibre opening device may be provided, as shown in FIG. 4.

The fibre opening device 120, shown in FIG. 4, includes a body 122 fixedto a hub arrangement 124 which is supported in bearings 126. A ring 128to which card clothing wire 130 is fixed is fitted around the body 122.A radially extending slot 132 extends through the ring 130 adjacent oneouter edge thereof, the slot 132 communicating with a radially extendingpassageway 134 provided in the body 122. An axially extending passageway136 communicates with the passageway 134 and leads away from the rollerbody 122. Similarly, a radially extending slot 138 extends through thering 130 adjacent the other outer edge thereof, the slot 138communicating with a radially extending passageway 140 which, in turn,communicates with an axially extending passageway 142 which leads awayfrom the body 122.

When the body 122 rotates air streams flow through the body as shown byarrows 144 and 146.

In each of the aforementioned embodiments, a slot or slots is/aresuitably provided in a part of the cylindrical surface of the openingroller between an outermost part of the carding wire and the peripheryof the cylindrical surface. In use, whilst a fibre sliver is still heldback under the control of a feed table and feed roller arrangement, airflow through the slot(s) tends to result in the axially outermost fibresof the sliver being brought under control so as to be urged intoengagement with the carding wire, thereby increasing the effectivenessof fibre separation by the opening roller. Additionally, a plurality ofholes may be provided between the windings of the carding wire forremoving microdust.

The reader's attention is directed to all papers and documents which arefiled concurrently with or previous to this specification in connectionwith this application and which are open to public inspection with thisspecification, and the contents of all such papers and documents areincorporated herein by reference.

All of the features disclosed in this specification (including anyaccompanying claims, abstract and drawings), and/or all of the steps ofany method or process so disclosed, may be combined in any combination,except combinations where at least some of such features and/or stepsare mutually exclusive.

Each feature disclosed in this specification (including any accompanyclaims, abstract and drawings), may be replaced by alternative featuresserving the same, equivalent or similar purpose, unless expressly statedotherwise. Thus, unless expressly stated, otherwise, each featuredisclosed is one example only of a generic series of equivalent orsimilar features.

The invention is not restricted to the details of the foregoingembodiment(s). The invention extends to any novel one, or any novelcombination, of the features disclosed in this specification (includingany accompanying claims, abstract and drawings), or to any novel one, orany novel combination, of the steps of any method or process sodisclosed.

We claim:
 1. A fiber opening device for use in a discontinuous spinningprocess, the opening device comprising an opening roller rotatablymounted about an axis and having a cylindrical working surface whichextends around said axis, opening elements being provided around saidworking surface and a space being defined between an axially outermostfiber opening element and an adjacent outer edge of the cylindricalworking surface, wherein pressure reduction means is provided forreducing pressure in or around that space, said pressure reduction meansbeing arranged to urge fibers into engagement with the working surface.2. A fibre opening device according to claim 1, wherein said pressurereduction means includes a passageway, a first end of which has anopening provided in or adjacent to said space.
 3. A fiber opening deviceaccording to claim 2, wherein said opening is provided in said space inthe cylindrical working surface.
 4. A fibre opening device according toclaim 3, wherein a second end of the passageway opens through a side ofthe opening roller.
 5. A fibre opening device according to claim 2,wherein an annular chamber is provided in said passageway, the chamberbeing coaxial with the rotational axis of the opening roller.
 6. A fiberopening device according to claim 5, wherein an annular opening whichleads into the annular chamber is defined in a side wall of the openingroller, said annular opening being coaxial with said axis of the openingroller.
 7. A fiber opening device according to claim 6, wherein an innerannular wall of said annular opening in said side wall is defined by astructure group consisting of a part of the nub and bearing housing. 8.A fibre opening device according to claim 6, wherein the radial width ofsaid annular opening is greater than 0.1 mm.
 9. A fibre opening deviceaccording to claim 2, wherein a plurality of openings and associatedpassageways are provided, said openings being circumferentially spacedaround the working surface of the opening roller at or adjacent to theouter periphery thereof.
 10. A fiber opening device according to claim1, wherein said opening roller of said device has an end face whichextends perpendicularly to said axis of said opening roller, and whereinan opening is provided adjacent to the opening roller in a part having asurface which faces said end face, said opening leading into apassageway in order to provide said pressure reduction means.
 11. Afibre opening device according to claim 1, wherein a pressure reductionmeans is provided adjacent to each outer edge of the cylindrical workingsurface.
 12. A fibre opening device according to claim 1, wherein saidcylindrical working surface of the opening roller is comprised by a ringwhich is releasably securable to a body of the opening device, an insidesurface of said ring defining, at least in part, the outer cylindricalboundary of a passageway which extends parallel to the axis of rotationof the opening roller.
 13. A ring for a fiber opening device accordingto claim 1, the ring having an axis and a cylindrical working surfacewhich extends around said axis and which includes means for attachmentof fiber opening elements, a space being defined between an axiallyoutermost portion of said means for attachment and an adjacent outeredge of the ring which is axially spaced from said axially outermostportion, wherein an opening is provided in said space which openingextends though said ring.
 14. A ring for a fiber opening deviceaccording to claim 1, the ring having an axis and a cylindrical workingsurface which extends around said axis and which includes attached fiberopening elements, a space being defined between an axially outermostfiber opening element and an adjacent outer edge of the ring which isaxially spaced from said attached fiber opening element, wherein anopening is provided in said space which opening extends through saidring.